Machinery Lubrication

Machinery Lubrication Sept Oct 2014

Machinery Lubrication magazine published by Noria Corporation

Issue link: http://www.e-digitaleditions.com/i/388231

Contents of this Issue

Navigation

Page 32 of 68

28 | September - October 2014 | www.machinerylubrication.com ow fast can your car go with a full tank of gas as opposed to just one gallon of gas? It would be practically the same, right? Not only would the car drive just as fast, but unless you want to consider the weight, there would be no difference in perfor- mance. Now imagine driving a car without a fuel tank gauge. After each refueling, you would have an increasing fear that your car could run out of gas at any moment. Your only solution would be to refuel at a frequency that was safely ahead of when you estimate the tank to be empty. Other- wise, you would regularly encounter moments of unexpected inoperability. Just like a car, lubricants generally perform as expected for extended periods of time without any dramatic signs of degradation. The remaining "fuel" in this case would be reserve additives or inversely related to contamination levels. Unfortu- nately, you don't have a gauge to display the remaining useful life of key additives. An antioxidant is an example of an additive that will be expended over its useful life until it becomes empty without warning. The effects of this are exponen- tially unfavorable. Before antioxidant additives are fully depleted, they act as radical scavengers, coming in contact with and defusing the precursors to oxidation byproducts and metallic catalysts. At the moment of contact, not only are these oxidation precursors rendered harmless, but the localized antioxidant additives become useless. Although this decreases the reserve oxidation stability of the remaining oil, there remains a functioning level of antioxidants in the lubricant. These types of additives are consid- ered sacrificial because they are consumed as they are used, just like fuel in your car. Their consumption is actually desired, as it means they are doing their job. Typi- cally, the majority of additives in a lubricant will be sacrificial, including antioxidants, detergents, anti-wear addi- tives, rust and corrosion inhibitors, demulsif ying agents, and dispersants. So what happens when an additive becomes depleted? Without antioxidants, oxidation byproducts are allowed to corrode equipment parts, thickening the oil and reducing the base oil's lubricating properties. The rate of lubricant failure, and consequently machine failure, increases rapidly — the same way your car may sputter to a stop as it runs out of fuel. The most effective way to defend against the silent dangers of impending Benne t t Fi t ch | Nori a Corpor at ioN Lessons in Lubrication the sIleNt dANGer of Abrupt lubricant FAIlUre The Dangers of ConTaMinaTion CoNTAMINATIoN rATeS CAN ALSo be A SILeNT dANger. All lubricants have some level of solid contam- inants. even with new lubricants, complete cleanliness is unattainable. The key is to ensure that there are more contaminants being filtered out than contaminants being generated or ingressed. The problem arises when too many contaminants are allowed to exist in the workings of a machine. These contaminants can generate more contaminants through three-body abrasion. This cyclical act proliferates to a point where the filter cannot keep up. So while oil analysis may show that contaminant levels remain at an acceptable rate, it only takes a moderate increase in contamination to create an exponential spike toward machine failure. H

Articles in this issue

Links on this page

Archives of this issue

view archives of Machinery Lubrication - Machinery Lubrication Sept Oct 2014